In conventional systems of the Cyclotron type the particles are accelerated in a high-frequency electric field set up between hollow segmental electrodes, termed dees, the particles being constrained by a constant transverse magnetic field to spiral outwardly in a path centered on the field axis. The frequency of the electric driving field, acting intermittently upon the particles, must be correlated with their mass/charge ratio which therefore must be the same for all particles to be accelerated in synchronism. Moreover, the sense of acceleration and therefore the direction of motion depends on the polarity of the particle. If an attempt were made to accelerate a gaseous plasma in such systems, the polarity dependent direction of motion of the particles and the diversity of their mass-charge ratios would cause turbulence and untimely collisions between particles travelling at different velocities and directions; the resulting non-uniformity of particle velocities prevents the attainment of controlled conditions for the desired nuclear or chemical reactions.
Similar considerations apply to Betatrons and Tokomak accelerators, in which particles of different polarities are driven in opposite directions by a stationary magnetic field perpendicular to their orbital plane whose intensity increases monotonically during each propulsion cycle. When driving a plasma, most of the field energy is transferred to the electrons, which causes power losses and excessive turbulence of the plasma flow.
Another conventional way of imparting high kinetic energies to molecular particles is by heating a gas to a very high temperature, such as that produced by a plasma arc. This method of particle acceleration, however, is uneconomical since it produces a wide range of particle energies, not confined to the characteristic energy level of a desired reaction, in accordance with the Maxwell-Boltzmann law of energy distribution in a heated gas. Moreover, the unwanted energy bands may also give rise to parasitic side reactions.
In an application filed on even date herewith by one of us, Thomas I. Ress, Ser. No. 418,858 filed 11-26-73 and now U.S. Pat. No. 3,935,503 there has been disclosed a system for the synchronous entrainment of charged particles (electrons and ions) by a magnetic field revolving with constant angular velocity about the axis of a closed vessel of generally cylindrical or toroidal configuration, the angular velocity of this field so chosen that the particles acquire the desired energy. If the power of the magnetic drive field per unit volume exceeds a critical magnitude, such rotary accelerator configurations cause, during start-up, many particle collisions and rapid ionization of the entire gas volume admitted into the vessel, followed by the acceleration of a circular plasma stream to an average velocity equal to the velocity of the rotary drive field. An auxiliary magnetostatic field aligned with the axis of field rotation limits the radially outward excursions of the plasma particles.